1. Field of Invention
This invention relates to an all-terrain vehicle (ATV), and more particularly to an ATV having an improved fuel tank with an improved fuel tank location.
2. Description of the Related Art
ATVs are popular, largely because of their compact design and the utility they provide. ATVs are designed to move across flat and rugged terrain with relative ease. The compact design of an ATV gives it a high power-to-weight ratio, thereby allowing the ATV to travel across terrain that a full-sized four wheel drive vehicle could not.
In order for the ATV to be as stable as possible, it is desirable for the ATV to have a center of gravity as low as possible, yet still have substantial clearance over the rugged terrain. The compactness of the ATV forces its parts, and weight, upward, thereby raising the center of gravity. Thus, a trade-off exists with overall dimensions and clearances of the ATV and its overall stability.
Due to the compact design of an ATV, space between the parts of an ATV is very tight. A frame holds the entire ATV together and the engine generally sits in the center of the frame. Other components of the ATV are placed around the engine where appropriate space is available and are typically positioned to facilitate access thereto. For instance, the fuel tank typically is positioned so that it is readily accessible and so that the ATV can be easily fueled.
FIG. 1a illustrates a side view of a prior art ATV that is disclosed in U.S. Pat. No. 4,757,872 ('872 patent). FIG. 1b provides a top view of the same prior art ATV shown in FIG. 1a without many of the components that are located on top of the ATV. The '872 patent discloses an ATV 10 with a body frame 14 and a fuel tank 12 located towards the rear of the ATV 10. The body frame 14 is a conventional “space” frame that utilizes a relatively complex network of interconnected tubular members. The body frame 14 includes laterally extending cross members 15. The fuel tank 12 is disposed on one side of a longitudinal centerline 18 of the body frame 14 and is essentially hung from the laterally extending cross members 15 located at the top of the frame 14. An exhaust muffler 16 is disposed on the other side of the longitudinal centerline 18 of the body frame 14. By locating the fuel tank 12 just beneath the top of the body frame 14, the fuel tank 12 is relatively easy to access.
On some prior art ATVs, the fuel tank is disposed even further towards the rear of the ATV and directly above the axle of one of the rear wheels, while the muffler is disposed directly above the axle of the opposite rear wheel. The placement of the fuel tank towards the rear of the ATV, as illustrated in FIGS. 1a and 1b, and especially over the axle of one of the rear wheels, creates two potential problems. First, it causes the center of gravity for the fuel tank, and, hence for the entire ATV to be relatively high, thereby decreasing stability of the ATV. Second, by having the fuel tank located adjacent one rear wheel, the fuel tank must have walls thick enough to withstand the impact of foreign objects, such as rocks, that are kicked up by the wheel. This necessarily increases the weight of the fuel tank, further contributing to a high center of gravity and decreased stability for the ATV.
FIG. 2 illustrates a different prior art ATV that is disclosed in U.S. Pat. No. 5,791,431 ('431 patent). The '431 patent discloses an ATV 20 with a fuel tank 22 that is disposed on the upper portion of the frame (not shown), in between a steering handlebar 24 and a passenger seat 26. Although the fuel tank 22 is easily accessible, the fuel tank 22 is above the engine (not shown) and contributes to a relatively high center of gravity, as in the previous example. Again, the problem with this fuel tank 22 location is that the center of gravity of the fuel tank 22 is relatively high, making the ATV 20 more top heavy and less stable than is desired.
Thus, there is a need for an improved fuel tank position on the ATV so that the stability of the ATV may be improved. Specifically, there is a need to locate the fuel tank as low as possible on the ATV and away from the wheels of the ATV, while still providing accessibility to the fuel tank.